syncEffect

Like effect, but it runs immediately when created — even in the middle of an update — and its re-runs fire ahead of regular effects within the same batch. pota itself uses it where setup must complete before user code observes it: context providers and catchError boundaries. Pick it when creation-time or ordering guarantees matter — for everything else, effect is the right primitive.

Arguments

name	type	description
fn	() => void	function whose tracked reads become its deps

Returns: void.

Examples

Synchronous snapshot

An effect created during a render runs at the end of the render batch — after the component body has returned. syncEffect runs during creation, so snapshot is already populated when the static text below reads it.

import { render, signal, syncEffect } from 'pota'

function App() {
	const count = signal(1)
	let snapshot

	syncEffect(() => {
		snapshot = count.read()
	})

	return (
		<div>
			<p>captured: {snapshot}</p>
			<button on:click={() => count.update(n => n + 1)}>
				bump (the variable updates; the static text keeps the first
				snapshot)
			</button>
		</div>
	)
}

render(App)